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import torch | |
import torch.nn as nn | |
import torch.nn.functional as F | |
import random | |
import math | |
from inspect import isfunction | |
from einops import rearrange, repeat | |
from torch import nn, einsum | |
def exists(val): | |
return val is not None | |
def default(val, d): | |
if exists(val): | |
return val | |
return d() if isfunction(d) else d | |
class CrossAttention(nn.Module): | |
def __init__(self, query_dim, context_dim=None, heads=8, dim_head=64, dropout=0.): | |
super().__init__() | |
inner_dim = dim_head * heads | |
context_dim = default(context_dim, query_dim) | |
self.scale = dim_head ** -0.5 | |
self.heads = heads | |
self.to_q = nn.Linear(query_dim, inner_dim, bias=False) | |
self.to_k = nn.Linear(context_dim, inner_dim, bias=False) | |
self.to_v = nn.Linear(context_dim, inner_dim, bias=False) | |
self.to_out = nn.Sequential( | |
nn.Linear(inner_dim, query_dim), | |
nn.Dropout(dropout) | |
) | |
def forward(self, x, context=None, mask=None, return_attn=False, need_softmax=True, guidance_mask=None, | |
forward_layout_guidance=False): | |
h = self.heads | |
b = x.shape[0] | |
q = self.to_q(x) | |
context = default(context, x) | |
k = self.to_k(context) | |
v = self.to_v(context) | |
q, k, v = map(lambda t: rearrange(t, 'b n (h d) -> (b h) n d', h=h), (q, k, v)) | |
sim = einsum('b i d, b j d -> b i j', q, k) * self.scale | |
if forward_layout_guidance: | |
# sim: (B * phase_num * h, HW, 77), b = B * phase_num | |
# guidance_mask: (B, phase_num, 64, 64) | |
HW = sim.shape[1] | |
H = W = int(math.sqrt(HW)) | |
guidance_mask = F.interpolate(guidance_mask, size=(H, W), mode='nearest') # (B, phase_num, H, W) | |
sim = sim.view(b, h, HW, 77) | |
guidance_mask = guidance_mask.view(b, 1, HW, 1) | |
guidance_mask[guidance_mask == 1] = 5.0 | |
guidance_mask[guidance_mask == 0] = 0.1 | |
sim[:, :, :, 1:] = sim[:, :, :, 1:] * guidance_mask | |
sim = sim.view(b * h, HW, 77) | |
if exists(mask): | |
mask = rearrange(mask, 'b ... -> b (...)') | |
max_neg_value = -torch.finfo(sim.dtype).max | |
mask = repeat(mask, 'b j -> (b h) () j', h=h) | |
sim.masked_fill_(~mask, max_neg_value) | |
if need_softmax: | |
attn = sim.softmax(dim=-1) | |
else: | |
attn = sim | |
out = einsum('b i j, b j d -> b i d', attn, v) | |
out = rearrange(out, '(b h) n d -> b n (h d)', h=h) | |
if return_attn: | |
attn = attn.view(b, h, attn.shape[-2], attn.shape[-1]) | |
return self.to_out(out), attn | |
else: | |
return self.to_out(out) | |
class LayoutAttention(nn.Module): | |
def __init__(self, query_dim, context_dim=None, heads=8, dim_head=64, dropout=0., use_lora=False): | |
super().__init__() | |
inner_dim = dim_head * heads | |
context_dim = default(context_dim, query_dim) | |
self.use_lora = use_lora | |
self.scale = dim_head ** -0.5 | |
self.heads = heads | |
self.to_q = nn.Linear(query_dim, inner_dim, bias=False) | |
self.to_k = nn.Linear(context_dim, inner_dim, bias=False) | |
self.to_v = nn.Linear(context_dim, inner_dim, bias=False) | |
self.to_out = nn.Sequential( | |
nn.Linear(inner_dim, query_dim), | |
nn.Dropout(dropout) | |
) | |
def forward(self, x, context=None, mask=None, return_attn=False, need_softmax=True, guidance_mask=None): | |
h = self.heads | |
b = x.shape[0] | |
q = self.to_q(x) | |
context = default(context, x) | |
k = self.to_k(context) | |
v = self.to_v(context) | |
q, k, v = map(lambda t: rearrange(t, 'b n (h d) -> (b h) n d', h=h), (q, k, v)) | |
sim = einsum('b i d, b j d -> b i j', q, k) * self.scale | |
_, phase_num, H, W = guidance_mask.shape | |
HW = H * W | |
guidance_mask_o = guidance_mask.view(b * phase_num, HW, 1) | |
guidance_mask_t = guidance_mask.view(b * phase_num, 1, HW) | |
guidance_mask_sim = torch.bmm(guidance_mask_o, guidance_mask_t) # (B * phase_num, HW, HW) | |
guidance_mask_sim = guidance_mask_sim.view(b, phase_num, HW, HW).sum(dim=1) | |
guidance_mask_sim[guidance_mask_sim > 1] = 1 # (B, HW, HW) | |
guidance_mask_sim = guidance_mask_sim.view(b, 1, HW, HW) | |
guidance_mask_sim = guidance_mask_sim.repeat(1, self.heads, 1, 1) | |
guidance_mask_sim = guidance_mask_sim.view(b * self.heads, HW, HW) # (B * head, HW, HW) | |
sim[:, :, :HW][guidance_mask_sim == 0] = -torch.finfo(sim.dtype).max | |
if exists(mask): | |
mask = rearrange(mask, 'b ... -> b (...)') | |
max_neg_value = -torch.finfo(sim.dtype).max | |
mask = repeat(mask, 'b j -> (b h) () j', h=h) | |
sim.masked_fill_(~mask, max_neg_value) | |
# attention, what we cannot get enough of | |
if need_softmax: | |
attn = sim.softmax(dim=-1) | |
else: | |
attn = sim | |
out = einsum('b i j, b j d -> b i d', attn, v) | |
out = rearrange(out, '(b h) n d -> b n (h d)', h=h) | |
if return_attn: | |
attn = attn.view(b, h, attn.shape[-2], attn.shape[-1]) | |
return self.to_out(out), attn | |
else: | |
return self.to_out(out) | |
class BasicConv(nn.Module): | |
def __init__(self, in_planes, out_planes, kernel_size, stride=1, padding=0, dilation=1, groups=1, relu=True, bn=False, bias=False): | |
super(BasicConv, self).__init__() | |
self.out_channels = out_planes | |
self.conv = nn.Conv2d(in_planes, out_planes, kernel_size=kernel_size, stride=stride, padding=padding, dilation=dilation, groups=groups, bias=bias) | |
self.bn = nn.BatchNorm2d(out_planes,eps=1e-5, momentum=0.01, affine=True) if bn else None | |
self.relu = nn.ReLU() if relu else None | |
def forward(self, x): | |
x = self.conv(x) | |
if self.bn is not None: | |
x = self.bn(x) | |
if self.relu is not None: | |
x = self.relu(x) | |
return x | |
class Flatten(nn.Module): | |
def forward(self, x): | |
return x.view(x.size(0), -1) | |
class ChannelGate(nn.Module): | |
def __init__(self, gate_channels, reduction_ratio=16, pool_types=['avg', 'max']): | |
super(ChannelGate, self).__init__() | |
self.gate_channels = gate_channels | |
self.mlp = nn.Sequential( | |
Flatten(), | |
nn.Linear(gate_channels, gate_channels // reduction_ratio), | |
nn.ReLU(), | |
nn.Linear(gate_channels // reduction_ratio, gate_channels) | |
) | |
self.pool_types = pool_types | |
def forward(self, x): | |
channel_att_sum = None | |
for pool_type in self.pool_types: | |
if pool_type=='avg': | |
avg_pool = F.avg_pool2d( x, (x.size(2), x.size(3)), stride=(x.size(2), x.size(3))) | |
channel_att_raw = self.mlp( avg_pool ) | |
elif pool_type=='max': | |
max_pool = F.max_pool2d( x, (x.size(2), x.size(3)), stride=(x.size(2), x.size(3))) | |
channel_att_raw = self.mlp( max_pool ) | |
elif pool_type=='lp': | |
lp_pool = F.lp_pool2d( x, 2, (x.size(2), x.size(3)), stride=(x.size(2), x.size(3))) | |
channel_att_raw = self.mlp( lp_pool ) | |
elif pool_type=='lse': | |
# LSE pool only | |
lse_pool = logsumexp_2d(x) | |
channel_att_raw = self.mlp( lse_pool ) | |
if channel_att_sum is None: | |
channel_att_sum = channel_att_raw | |
else: | |
channel_att_sum = channel_att_sum + channel_att_raw | |
scale = F.sigmoid( channel_att_sum ).unsqueeze(2).unsqueeze(3).expand_as(x) | |
return x * scale | |
def logsumexp_2d(tensor): | |
tensor_flatten = tensor.view(tensor.size(0), tensor.size(1), -1) | |
s, _ = torch.max(tensor_flatten, dim=2, keepdim=True) | |
outputs = s + (tensor_flatten - s).exp().sum(dim=2, keepdim=True).log() | |
return outputs | |
class ChannelPool(nn.Module): | |
def forward(self, x): | |
return torch.cat( (torch.max(x,1)[0].unsqueeze(1), torch.mean(x,1).unsqueeze(1)), dim=1 ) | |
class SpatialGate(nn.Module): | |
def __init__(self): | |
super(SpatialGate, self).__init__() | |
kernel_size = 7 | |
self.compress = ChannelPool() | |
self.spatial = BasicConv(2, 1, kernel_size, stride=1, padding=(kernel_size-1) // 2, relu=False) | |
def forward(self, x): | |
x_compress = self.compress(x) | |
x_out = self.spatial(x_compress) | |
scale = F.sigmoid(x_out) # broadcasting | |
return x * scale | |
class CBAM(nn.Module): | |
def __init__(self, gate_channels, reduction_ratio=16, pool_types=['avg', 'max'], no_spatial=False): | |
super(CBAM, self).__init__() | |
self.ChannelGate = ChannelGate(gate_channels, reduction_ratio, pool_types) | |
self.no_spatial=no_spatial | |
if not no_spatial: | |
self.SpatialGate = SpatialGate() | |
def forward(self, x): | |
x_out = self.ChannelGate(x) | |
if not self.no_spatial: | |
x_out = self.SpatialGate(x_out) | |
return x_out |